Seismic sources usually comprise arrays of individual seismic source elements. The most common marine seismic source elements are airguns, but other elements such as vibrators, waterguns and sparkers, etc., may also be used. The seismic source elements behave individually as point sources over the bandwidth of interest and are each characterized by a notional source signature, sometimes called the monopole source function.
Seismic source arrays exhibit directivity. This directivity may produce directivity patterns that are determined by the notional source signatures, the positions and the activation times of the source elements in the array. The reflected signal from the sea surface may strongly affect the directivity pattern
For some conditions, it is desirable that the source array should behave as closely as possible to a monopole source. Today's commercially available sources try to achieve this by reducing the array size such that the maximum array dimension is considerable smaller than the shortest wavelength of interest. However, this will not result in a monopole source spectrum when the sea surface reflection is taken into account. The resulting source will be a dipole. Embodiments of the present invention may provide a method for designing an improved monopole source configuration.